1. Field of the Invention
The present invention relates generally to behavior modifying chemicals which influence the behavior of spider mites as well as to miticides used to kill spider mites, and more particularly, to a novel miticidal composition combining farnesol and/or nerolidol in a controlled release form with a miticide to enhance the effectiveness of the miticide in controlling spider mite populations.
2. Description of the Prior Art
Spider mites, belonging to that family of Acari known scientifically as Tetranychidae, are a common form of agricultural pest which damage the foliage of agricultural crops, trees and ornamentals. Two species of spider mites which are common are the carmine spider mite (Tetranychus cinnabarinus) and the two-spotted spider mite (Tetranychus urticae), both of which can inflict damage and reduce yields in cotton fields and other crops.
Various miticides are presently available to combat infestations of spider mites by killing such pests. One popular miticide is dicofol, commercially available from Rohm & Haas Company of Philadelphia, Pa. under the trademark "KELTHANE". Another popular miticide is a micronized form of sulfur, commercially available from Cumberland International of Houston, Tex. under the trademark "SULFLOX". A third type of popular miticide is 2-[4[1,1 dimethyl ethyl]phenoxy] cyclohexyl-2-propynyl sulfite, commercially available from Uniroyal Chemical, a division of Uniroyal, Inc. of Naugatuck Connecticut under the trademark "COMIIE". While such miticides are generally effective against spider mites in the short term, spider mites reproduce rapidly, and resistant strains develop an increased tolerance of such miticides over a period of approximately three years. It is believed that spider mites must actually come in physical contact with such miticides in order to be killed thereby. However as compared with other types of agricultural pests, spider mites move relatively little and are therefore less likely to come in physical contact with applied miticides unless relatively large amounts of such miticides are applied. Apart from the significant expense of applying large amounts of such miticides to the foliage of the plants or trees to be protected, it is believed that the application of large doses of such miticides results in the development of tolerance to such miticides more quickly.
It is known that certain chemicals are naturally produced by the female of certain insect species and other pests in order to attract the male. Such naturally occurring sex attractants are known as pheromones. Various types of such sex pheromones have been chemically extracted from the female of such insects. In some instances, such sex pheromones can be synthetically produced. In still other instances, chemicals which are not naturally present in a species of insect or other pest are nonetheless found to attract, repel, or otherwise influence the behavior of the male and/or female insect or other pest. Such naturally occurring or synthetically produced chemicals will sometimes be collectively referred to herein as behavior modifying chemicals.
It is known that certain behavior modifying chemicals, some naturally produced by spider mites, affect the behavior of spider mites, either by attracting, repelling or arresting the male of the species. Studies reported by Regev and Cone indicate that female two-spotted spider mites produce a sex pheromone which attracts the male of the species to a quiescent female deutonymph and serves to retain the attracted male until the emergence of the adult female, at which time mating normally occurs; extracts of the spider mite female deutonymphs showed the presence of the sesquiterpene alcohol farnesol. The study by Regev and Cone, entitled "Evidence of Farnesol As a Male Sex Attractant of the Two-Spotted Spider Mite, Tetranychus urticae Koch (Acarina: Tetranychidae)", Environmental Entomology, April 1985, Vol. 4, No. 2, pp. 307-311, indicated that certain isomers of synthetically produced farnesol, at particular concentrations, were effective in attracting male spider mites. A further study by Regev and Cone, "Analysis of Pharate Female Twospotted Spider Mites for Nerolidol and Geraniol: Evaluation for Sex Attraction of Males", Environmental Entomology, February 1976, Vol. 5, No. 1, pp. 133-138, also revealed that the two-spotted spider mite female deutonymph also contains the sesquiterpene alcohol nerolidol; their study indicated that synthetic nerolidol, at particular concentrations, served to attract male two-spotted spider mites.
Both of the above-referenced studies reported by Regev and Cone reference other studies wherein it is reported that farnesol and/or nerolidol act as attractants for higher insects such as bees and moths. However, Regev and Cone state that, in the case of higher insects, the sex attractant is airborne and detected by the male at a distance. In contrast, Regev and Cone report that an airborne sex attractant would not be of great advantage in the case of the spider mite because most offspring live in the same site where eggs are laid. Regev and Cone explain that, if the mother is fertilized, both sexes are produced from those eggs, hence, mates are not far from each other to necessitate an airborne kind of sex attractant. Regev and Cone further state that, with respect to the two-spotted spider mite, it is the tactile chemical stimulus which is important insofar as attracting male spider mites.
The concept of combining volatile sex attractants with insecticides for controlling populations of higher insects is known. For example, U.S. Pat. No. 4,122,165, issued to Kinzer et al., and Australian Patent No. 477,526, issued to Thuron Industries, Inc., both describe the combination of the sex pheromone cis-9-tricosene (muscalure) with an insecticide to control house fly (Musca domestica) populations.
Higher insects such as bees, moths and house flies, are highly mobile, and the male and female of the species must mate in order to reproduce. Given such characteristics, it is not surprising that airborne sex attractants have proven effective to enhance the effect of pesticides on such insect species. In contrast, spider mites, which are not true insects, exhibit parthenogenesis,i.e., female spider mites can reproduce males without first mating with a male spider mite. In addition, mites are relatively small and do not move far from the site from which they are hatched. Furthermore, as set forth above with respect to the studies conducted by Regev and Cone, sex attractants in spider mites operate principally by tactile chemical stimulus, leading Regev and Cone to conclude that an airborne sex attractant would not be of great advantage in the case of the spider mite.
In view of the distinct differences in the mating patterns, operation of sex attractants, and general behavior as between spider mites and higher insect forms, the ability of spider mite behavior modifying chemicals to influence the effectiveness of miticides is not readily apparent and could not have been predicted.
It is an object of the present invention to provide a miticidal composition which includes a miticide and which provides significantly improved effectiveness to control spider mite populations as compared with usage of the miticide alone.
It is another object of the present invention to provide such a miticidal composition which allows lesser application rates of conventional miticides than those presently used without reducing the level of control of spider mite populations.
It is still another object of the present invention to provide such a miticidal composition including a behavior modifying chemical which tends to increase the likelihood that spider mites will come in contact with an applied miticide.
It is a further object of the present invention to provide such a miticidal composition in a form which slowly releases such a behavior modifying chemical to prevent the same from dissipating too rapidly.
It is still a further object of the present invention to provide compositions in the form of solutions, emulsions, dispersions, powders, dusts, granules, pellets and the like adapted to be combined with a conventional miticide in order to easily form such an improved miticidal composition.
Yet another object of the present invention is to provide a method of controlling spider mite populations in the foliage of agricultural fields, trees, greenhouses, gardens and homes wherever there are plants susceptible to spider mite damage, through the application of such a miticidal composition.
These and other objects of the present invention will become more apparent to those skilled in the art as the description thereof proceeds.